<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script type="text/javascript" src="./jquery/jquery-1.12.4.min.js"></script>

    <script type="text/javascript" src="./jquery/demo3.js"></script>

    <style type="text/css">
        .hide{
            display: none;
        }

        .show{
            display: block;
        }
    </style>
</head>

<body>
<div class="box1">box1111</div>
<div class="box2">box2222</div>
<div class="box3">box3333</div>
<div class="box4">box4444</div>
<a href="https://www.baidu.com">百度</a>


<script type="text/javascript">
    var b1 = $('.box1');
    var b2 = $('.box2');

    //jquery设置元素样式
    b1.css('width','300px');
    b1.css('background','red');

    b2.css({
        background:'cyan',
        width:'200px'
    });

        b3 = $('a');
        console.log(b3.attr('href'));
        // b3.css()

</script>


</body>
</html>